Pub Date : 2025-03-19DOI: 10.1016/j.scriptamat.2025.116649
Ke Xu , Shouzhe Dong , Huayu Yang , Changqing Guo , Deshan Liang , Jing Wang , Houbing Huang
Hopfions are widely involved in topology, group theory, optics, etc. Recently Hopfion rings have been successfully characterized in a magnet, which makes them promising objects for electronic information applications. Here, we reveal that high-density polar transitions at domain boundaries are a condition for topological domain generation. Based on this, we investigate polar Hopf rings in the incommensurate antiferroelectric, which consist of two intertwined vortices and are mathematically equivalent to alink in topology. The superposition of three-dimensional high-frequency polar waves with different orientations at domain boundaries is responsible for the stability of polar Hopf rings. Furthermore, we demonstrate the reversible switching between polar Hopf rings and trivial domain by an electron beam. Our findings of atomic-scale Hopf rings may provide direction for the design of next-generation high-density electronic information devices.
{"title":"Polar Hopf rings emerge in antiferroelectrics","authors":"Ke Xu , Shouzhe Dong , Huayu Yang , Changqing Guo , Deshan Liang , Jing Wang , Houbing Huang","doi":"10.1016/j.scriptamat.2025.116649","DOIUrl":"10.1016/j.scriptamat.2025.116649","url":null,"abstract":"<div><div>Hopfions are widely involved in topology, group theory, optics, etc. Recently Hopfion rings have been successfully characterized in a magnet, which makes them promising objects for electronic information applications. Here, we reveal that high-density polar transitions at domain boundaries are a condition for topological domain generation. Based on this, we investigate polar Hopf rings in the incommensurate antiferroelectric, which consist of two intertwined vortices and are mathematically equivalent to a<span><math><mrow><mspace></mspace><msubsup><mn>2</mn><mn>1</mn><mn>2</mn></msubsup><mspace></mspace></mrow></math></span>link in topology. The superposition of three-dimensional high-frequency polar waves with different orientations at domain boundaries is responsible for the stability of polar Hopf rings. Furthermore, we demonstrate the reversible switching between polar Hopf rings and trivial domain by an electron beam. Our findings of atomic-scale Hopf rings may provide direction for the design of next-generation high-density electronic information devices.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116649"},"PeriodicalIF":5.3,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bismuth ferrite nanoislands offer unique advantages in ferroelectric applications due to their ability to form stable topological vortex domains, which are crucial for advanced device designs. These vortex domains, driven by topological properties, hold significant potential for enhancing non-volatile memory and energy storage applications. In this study, we systematically investigate the effects of three key geometric factors—height, length-to-height ratio, and slope—on the stability of vortex domains using phase-field simulations. Our results demonstrate that larger length-to-height ratios, higher slopes, and smaller heights promote the formation and stability of vortex domains. Conversely, negative slopes hinder vortex formation, but increasing the length-to-height ratio compensates for this effect, stabilizing switchable vortex domains. A phase diagram is constructed to illustrate the combined influence of these three parameters, identifying conditions that favor vortex stability. These findings provide valuable insights into the geometric design of ferroelectric nanoislands with tailored topological domain structures, which could significantly impact the development of next-generation ferroelectric devices and logic units based on topological vortex configurations.
{"title":"Size effects of topological vortex domain in BiFeO3 nanoisland by phase-field simulations","authors":"Shiyu Tang , Changqing Guo , Jing Wang , Houbing Huang","doi":"10.1016/j.scriptamat.2025.116633","DOIUrl":"10.1016/j.scriptamat.2025.116633","url":null,"abstract":"<div><div>Bismuth ferrite nanoislands offer unique advantages in ferroelectric applications due to their ability to form stable topological vortex domains, which are crucial for advanced device designs. These vortex domains, driven by topological properties, hold significant potential for enhancing non-volatile memory and energy storage applications. In this study, we systematically investigate the effects of three key geometric factors—height, length-to-height ratio, and slope—on the stability of vortex domains using phase-field simulations. Our results demonstrate that larger length-to-height ratios, higher slopes, and smaller heights promote the formation and stability of vortex domains. Conversely, negative slopes hinder vortex formation, but increasing the length-to-height ratio compensates for this effect, stabilizing switchable vortex domains. A phase diagram is constructed to illustrate the combined influence of these three parameters, identifying conditions that favor vortex stability. These findings provide valuable insights into the geometric design of ferroelectric nanoislands with tailored topological domain structures, which could significantly impact the development of next-generation ferroelectric devices and logic units based on topological vortex configurations.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116633"},"PeriodicalIF":5.3,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intermetallics are generally brittle at room temperature, severely limiting their applications. Using CoAl 100 nm/Fe 10 nm nanolaminate as a model system, we demonstrate a strategy for improving deformability of brittle intermetallics via introducing mobile dislocations across coherent interfaces. High-density pre-existing mobile dislocations are introduced into Fe layers via ion peening. In situ micropillar compression tests show the model system has high yield strength, 3.5 GPa, and sustainable work hardening to 5 GPa with substantial uniform plastic deformation, exhibiting superior strength-deformability synergy. Transmission electron microscopy studies reveal the mobile dislocations continuously propagate from Fe into CoAl across the coherent interface, accommodating the considerable plastic deformation. This study provides a fresh perspective for enhancing room temperature plasticity in a wide range of brittle materials.
{"title":"Improving deformability of brittle intermetallics via introducing mobile dislocations across coherent interfaces","authors":"Ke Xu , Anand Mathew , Zhongxia Shang , Yifan Zhang , Chao Shen , Benson Kunhung Tsai , Jianan Shen , Haiyan Wang , Xinghang Zhang","doi":"10.1016/j.scriptamat.2025.116638","DOIUrl":"10.1016/j.scriptamat.2025.116638","url":null,"abstract":"<div><div>Intermetallics are generally brittle at room temperature, severely limiting their applications. Using CoAl 100 nm/Fe 10 nm nanolaminate as a model system, we demonstrate a strategy for improving deformability of brittle intermetallics via introducing mobile dislocations across coherent interfaces. High-density pre-existing mobile dislocations are introduced into Fe layers via ion peening. <em>In situ</em> micropillar compression tests show the model system has high yield strength, 3.5 GPa, and sustainable work hardening to 5 GPa with substantial uniform plastic deformation, exhibiting superior strength-deformability synergy. Transmission electron microscopy studies reveal the mobile dislocations continuously propagate from Fe into CoAl across the coherent interface, accommodating the considerable plastic deformation. This study provides a fresh perspective for enhancing room temperature plasticity in a wide range of brittle materials.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116638"},"PeriodicalIF":5.3,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-14DOI: 10.1016/j.scriptamat.2025.116647
Yang Su, Josh Kacher
In situ high-resolution electron backscattered diffraction is combined with electron channeling contrast imaging to study the interactions of dislocations and associated stress fields near grain boundaries in austenitic stainless steel 316L samples at the early stages of fatigue. The influence of fatigue stress amplitude on strain irreversibilities at grain boundaries was also investigated. It was found that dislocation pile-ups formed at 150 or 220 MPa are fully or partially released by reversing the loading direction, and the stress fields associated with those pile-ups are also fully or partially reversible between maximum tension and compression. In contrast, the dislocation networks formed at 300 MPa remain stable and irreversible. The cause of irreversibility at 150 MPa and 220 MPa was found to be dislocation debris generated by reversible dislocation glide, while at 300 MPa the irreversibility is mainly a result of tangles formed by multiple slip systems intersecting each other.
{"title":"Early stage strain localization at grain boundaries during fatigue studied using in situ electron channeling contrast imaging and high-resolution electron backscattered diffraction","authors":"Yang Su, Josh Kacher","doi":"10.1016/j.scriptamat.2025.116647","DOIUrl":"10.1016/j.scriptamat.2025.116647","url":null,"abstract":"<div><div><em>In situ</em> high-resolution electron backscattered diffraction is combined with electron channeling contrast imaging to study the interactions of dislocations and associated stress fields near grain boundaries in austenitic stainless steel 316L samples at the early stages of fatigue. The influence of fatigue stress amplitude on strain irreversibilities at grain boundaries was also investigated. It was found that dislocation pile-ups formed at 150 or 220 MPa are fully or partially released by reversing the loading direction, and the stress fields associated with those pile-ups are also fully or partially reversible between maximum tension and compression. In contrast, the dislocation networks formed at 300 MPa remain stable and irreversible. The cause of irreversibility at 150 MPa and 220 MPa was found to be dislocation debris generated by reversible dislocation glide, while at 300 MPa the irreversibility is mainly a result of tangles formed by multiple slip systems intersecting each other.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116647"},"PeriodicalIF":5.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-14DOI: 10.1016/j.scriptamat.2025.116652
Ronit Roy , Haozheng J. Qu , Keyou S. Mao , Janelle P. Wharry
The objective of this study is to understand the mechanical aspects of chloride-induced stress corrosion cracking (CISCC) in austenitic stainless steel. CISCC is a critical degradation mode in austenitic stainless steel, so understanding its mechanisms is essential for predicting material integrity and lifetime. Here, CISCC is studied by transmission Kikuchi diffraction and transmission electron microscopy for two cases: propagation into a lower Schmid factor grain and a higher Schmid factor grain. The evolution of deformation fields near the crack-tip is estimated through local misorientations and geometrically necessary dislocations, and are more severe in the lower Schmid factor grain. In both grain types, cross slips are distributed closer to the crack, while co-planar slips appear away from the crack, revealing consistent crack-tip deformations. Strain-induced α’-martensite transformations occur in the higher Schmid factor grain. These results imply that grain texture can be used to predict and mitigate CISCC propagation in austenitic stainless steel.
{"title":"Chloride-induced stress corrosion crack propagation mechanisms in austenitic stainless steel are mechanically driven","authors":"Ronit Roy , Haozheng J. Qu , Keyou S. Mao , Janelle P. Wharry","doi":"10.1016/j.scriptamat.2025.116652","DOIUrl":"10.1016/j.scriptamat.2025.116652","url":null,"abstract":"<div><div>The objective of this study is to understand the mechanical aspects of chloride-induced stress corrosion cracking (CISCC) in austenitic stainless steel. CISCC is a critical degradation mode in austenitic stainless steel, so understanding its mechanisms is essential for predicting material integrity and lifetime. Here, CISCC is studied by transmission Kikuchi diffraction and transmission electron microscopy for two cases: propagation into a lower Schmid factor grain and a higher Schmid factor grain. The evolution of deformation fields near the crack-tip is estimated through local misorientations and geometrically necessary dislocations, and are more severe in the lower Schmid factor grain. In both grain types, cross slips are distributed closer to the crack, while co-planar slips appear away from the crack, revealing consistent crack-tip deformations. Strain-induced α’-martensite transformations occur in the higher Schmid factor grain. These results imply that grain texture can be used to predict and mitigate CISCC propagation in austenitic stainless steel.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116652"},"PeriodicalIF":5.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-13DOI: 10.1016/j.scriptamat.2025.116636
Saeed Sadeghpour , Roohallah Surki Aliabad , Shubo Wang , Vahid Javaheri , Harishchandra Singh , Mahesh Somani , Dong-Woo Suh , Pentti Karjalainen , Jukka Komi
In-depth analysis of phase transformations during continuous heating (2.4 °C/s) of 50 % cold-rolled Fe-6Mn-2Al-1Si-0.4C (wt.%) steel with 32 % pre-existing austenite was conducted using in-situ high-energy synchrotron X-ray diffraction and microstructural characterisation. Significant austenite decomposition was found to occur in two stages between 226 and 530 °C and 530–600 °C, involving bainitic transformation and cementite precipitation, respectively, reducing the austenite fraction to 17.5 %. Lattice parameter changes suggested C enrichment in austenite during bainite formation and C and Mn depletion during precipitation. The austenite fraction increased around 650 °C, yielding 8 % new austenite by 680 °C in ∼40 s and 7 % during isothermal holding at 680 °C for 600 s. A further 3 % decrease during cooling, presumably due to pearlite formation, resulted in a final austenite fraction of 29.5 %, slightly below the initial level but further enriched in C and Mn. These findings provide insights into austenite evolution during thermal processing of cold-rolled medium Mn steels.
{"title":"Significant austenite decomposition during slow heating of cold-rolled medium Mn steel with a high fraction of pre-existing austenite","authors":"Saeed Sadeghpour , Roohallah Surki Aliabad , Shubo Wang , Vahid Javaheri , Harishchandra Singh , Mahesh Somani , Dong-Woo Suh , Pentti Karjalainen , Jukka Komi","doi":"10.1016/j.scriptamat.2025.116636","DOIUrl":"10.1016/j.scriptamat.2025.116636","url":null,"abstract":"<div><div>In-depth analysis of phase transformations during continuous heating (2.4 °C/s) of 50 % cold-rolled Fe-6Mn-2Al-1Si-0.4C (wt.%) steel with 32 % pre-existing austenite was conducted using in-situ high-energy synchrotron X-ray diffraction and microstructural characterisation. Significant austenite decomposition was found to occur in two stages between 226 and 530 °C and 530–600 °C, involving bainitic transformation and cementite precipitation, respectively, reducing the austenite fraction to 17.5 %. Lattice parameter changes suggested C enrichment in austenite during bainite formation and C and Mn depletion during precipitation. The austenite fraction increased around 650 °C, yielding 8 % new austenite by 680 °C in ∼40 s and 7 % during isothermal holding at 680 °C for 600 s. A further 3 % decrease during cooling, presumably due to pearlite formation, resulted in a final austenite fraction of 29.5 %, slightly below the initial level but further enriched in C and Mn. These findings provide insights into austenite evolution during thermal processing of cold-rolled medium Mn steels.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116636"},"PeriodicalIF":5.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-13DOI: 10.1016/j.scriptamat.2025.116637
Hyunwook Nam , Sangwook Kim , Ichiro Fujii , Motoki Aruga , Shintaro Ueno , Yoshihiro Kuroiwa , Satoshi Wada
Ternary BiFeO3‒BaTiO3 (BFBT)-based ceramics often exhibit a higher piezoelectricity compared to binary BFBT ceramics. However, the origin of the enhanced piezoelectricity in ternary ceramics remains unclear. In this study, we investigated the role of the third composition by examining the pseudo-cubic symmetry of Bi(Mg0.5Ti0.5)O3 (BMT)-modified BFBT piezoelectric ceramics using high-energy synchrotron radiation X-ray diffraction and the Rietveld method. Our experimental results validate the critical influence of Bi ion off-centering displacement, as the largest Bi ion off-centering displacement at a specific third composition demonstrates the highest piezoelectric properties. The displacement of Bi ions varies with the Bi-O covalent bond length and repulsive interactions between the off-centered Bi and B-site cations. This study highlights the importance of the ionic radii of the B-site cations in the third composition for high-performance BFBT-based piezoelectric ceramics.
{"title":"Role of the third composition and its A-site cation off-centering mechanism in ternary BiFeO3‒BaTiO3-based piezoelectric ceramics","authors":"Hyunwook Nam , Sangwook Kim , Ichiro Fujii , Motoki Aruga , Shintaro Ueno , Yoshihiro Kuroiwa , Satoshi Wada","doi":"10.1016/j.scriptamat.2025.116637","DOIUrl":"10.1016/j.scriptamat.2025.116637","url":null,"abstract":"<div><div>Ternary BiFeO<sub>3</sub>‒BaTiO<sub>3</sub> (BFBT)-based ceramics often exhibit a higher piezoelectricity compared to binary BFBT ceramics. However, the origin of the enhanced piezoelectricity in ternary ceramics remains unclear. In this study, we investigated the role of the third composition by examining the pseudo-cubic symmetry of Bi(Mg<sub>0.5</sub>Ti<sub>0.5</sub>)O<sub>3</sub> (BMT)-modified BFBT piezoelectric ceramics using high-energy synchrotron radiation X-ray diffraction and the Rietveld method. Our experimental results validate the critical influence of Bi ion off-centering displacement, as the largest Bi ion off-centering displacement at a specific third composition demonstrates the highest piezoelectric properties. The displacement of Bi ions varies with the Bi-O covalent bond length and repulsive interactions between the off-centered Bi and B-site cations. This study highlights the importance of the ionic radii of the B-site cations in the third composition for high-performance BFBT-based piezoelectric ceramics.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116637"},"PeriodicalIF":5.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-12DOI: 10.1016/j.scriptamat.2025.116634
Yujun Zhao , Felix Großwendt , Maik Rajkowski , Parham Gemagami , Régis Poulain , Loïc Perrière , Jean-Philippe Couzinié , Sebastian Weber , Guillaume Laplanche , Tong Li
The role of O in the precipitation behavior at high temperatures of the equiatomic body-centered cubic (bcc) HfNbTaTiZr high-entropy alloy remains unclear and hence is investigated in this work. We employed transmission electron microscopy and atom probe tomography to reveal structural and compositional evolutions of precipitation in HfNbTaTiZr upon isothermal aging at 1200 °C. Due to the presence of O in the atmosphere, a Zr-Hf-rich hexagonal closed-packed (hcp) phase precipitates from the bcc matrix after 200 h. Due to the gradual uptake of O by the alloy from 200 h to 500 h, the Ti and O concentrations of the hcp phase increase. This results in the formation of an ordered phase in the hcp phase with a structure similar to Ti3O, whose number density and size slightly increase with time. As the hcp phase is increasingly reinforced by oxygen solutes and oxide precipitates, it becomes harder.
{"title":"Formation of an ordered phase in hcp precipitates during aging of bcc HfNbTaTiZr high-entropy alloy","authors":"Yujun Zhao , Felix Großwendt , Maik Rajkowski , Parham Gemagami , Régis Poulain , Loïc Perrière , Jean-Philippe Couzinié , Sebastian Weber , Guillaume Laplanche , Tong Li","doi":"10.1016/j.scriptamat.2025.116634","DOIUrl":"10.1016/j.scriptamat.2025.116634","url":null,"abstract":"<div><div>The role of O in the precipitation behavior at high temperatures of the equiatomic body-centered cubic (bcc) HfNbTaTiZr high-entropy alloy remains unclear and hence is investigated in this work. We employed transmission electron microscopy and atom probe tomography to reveal structural and compositional evolutions of precipitation in HfNbTaTiZr upon isothermal aging at 1200 °C. Due to the presence of O in the atmosphere, a Zr-Hf-rich hexagonal closed-packed (hcp) phase precipitates from the bcc matrix after 200 h. Due to the gradual uptake of O by the alloy from 200 h to 500 h, the Ti and O concentrations of the hcp phase increase. This results in the formation of an ordered phase in the hcp phase with a structure similar to Ti<sub>3</sub>O, whose number density and size slightly increase with time. As the hcp phase is increasingly reinforced by oxygen solutes and oxide precipitates, it becomes harder.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116634"},"PeriodicalIF":5.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-11DOI: 10.1016/j.scriptamat.2025.116646
Bo Song , Peng Dong , Xin Zhai , Dan Luo , Yanfei Gao
It has been found that nano-objects can spontaneously bond together, followed by a continuous growth of the welded area, even at low homologous temperatures. This so-named “cold welding” phenomenon can be utilized in advanced small-scale manufacturing, thus offering a promising solution to the challenges in tuning functionality, durability, and performance of nano-materials and nano-devices. This study develops a kinetic model that incorporates various competing driving-forces, and delineates their dominant parametric regimes on a cold-welding map with respect to bonding fraction, temperature, and absolute feature sizes. Cold welding can now be understood as governed either by curvature driven or as Coble creep, thus solving contradictions in the explanations of many recent experiments.
{"title":"A cold-welding map incorporating various competing mechanisms and size effects","authors":"Bo Song , Peng Dong , Xin Zhai , Dan Luo , Yanfei Gao","doi":"10.1016/j.scriptamat.2025.116646","DOIUrl":"10.1016/j.scriptamat.2025.116646","url":null,"abstract":"<div><div>It has been found that nano-objects can spontaneously bond together, followed by a continuous growth of the welded area, even at low homologous temperatures. This so-named “cold welding” phenomenon can be utilized in advanced small-scale manufacturing, thus offering a promising solution to the challenges in tuning functionality, durability, and performance of nano-materials and nano-devices. This study develops a kinetic model that incorporates various competing driving-forces, and delineates their dominant parametric regimes on a cold-welding map with respect to bonding fraction, temperature, and absolute feature sizes. Cold welding can now be understood as governed either by curvature driven or as Coble creep, thus solving contradictions in the explanations of many recent experiments.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116646"},"PeriodicalIF":5.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1016/j.scriptamat.2025.116635
Jiri Houska, Stanislav Haviar, Jiri Capek, Radomir Cerstvy, Kalyani Shaji, Nirmal Kumar, Petr Zeman
In the context of our efforts to develop hydrogen gas sensors, two samples of ternary CuWO4 with the same crystalline structure have been prepared by two different non-equilibrium techniques. We show that the materials' structure is significantly different from the known stable one, and we identify that it is very similar to that of previously reported γ-CuMoO4. We use ab-initio calculations to confirm that the newly identified phase, γ-CuWO4, represents a local energy minimum. We present very similar calculated and measured lattice constants and X-ray diffractograms. We make a case that the low-temperature formation of the metastable γ-CuWO4 phase is facilitated by easier kinetics and/or by Cu-rich composition of our samples, and we show that it converts to the stable phase after annealing to 600 °C.
{"title":"New polymorph γ-CuWO4 inspired by γ-CuMoO4: Experimental identification and theoretical verification","authors":"Jiri Houska, Stanislav Haviar, Jiri Capek, Radomir Cerstvy, Kalyani Shaji, Nirmal Kumar, Petr Zeman","doi":"10.1016/j.scriptamat.2025.116635","DOIUrl":"10.1016/j.scriptamat.2025.116635","url":null,"abstract":"<div><div>In the context of our efforts to develop hydrogen gas sensors, two samples of ternary CuWO<sub>4</sub> with the same crystalline structure have been prepared by two different non-equilibrium techniques. We show that the materials' structure is significantly different from the known stable one, and we identify that it is very similar to that of previously reported γ-CuMoO<sub>4</sub>. We use ab-initio calculations to confirm that the newly identified phase, γ-CuWO<sub>4</sub>, represents a local energy minimum. We present very similar calculated and measured lattice constants and X-ray diffractograms. We make a case that the low-temperature formation of the metastable γ-CuWO<sub>4</sub> phase is facilitated by easier kinetics and/or by Cu-rich composition of our samples, and we show that it converts to the stable phase after annealing to 600 °C.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"262 ","pages":"Article 116635"},"PeriodicalIF":5.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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